Mechanical Engineer - Cable Magnets
Commonwealth Fusion Systems
Other Engineering
Devens, MA, USA
USD 90k-145k / year + Equity
Posted on Nov 26, 2025
About Commonwealth Fusion Systems:
Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.
Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And working with policymakers and suppliers to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised nearly $3 billion in capital, making us the largest and leading private fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.
Join the power movement as a Mechanical Engineer – Cable Magnets
SPARC is the next step to commercial fusion, and it will be the first fusion device to demonstrate Q>1. As a Magnet Design Engineer on the Central Solenoid (CS) Magnet, you will be tasked with designing components that support one of the 3 primary magnet systems that are used to shape and drive the plasma. The CS magnet is a complicated mechanical system that operates in an extreme environment (high vacuum near absolute zero) and it relies on a range of fabrication methods including but not limited to composite layups, welding, forming, and machining. This position will involve all stages of the product lifecycle: blank-page design, CAD and analysis, sourcing and vendor support, testing support, production support, and peer review. The Magnet Design Engineer will work closely with teammates and peers on adjacent teams to ensure that work meets SPARC requirements and is aligned with the broader needs of CFS. The Magnet Design Engineer will present designs to an audience of peers and leadership (including executive leadership) in order to demonstrate that design objectives have been met, and to resolve technical concerns.
What you'll do:
- Design and analyze mechanical structures for the CS magnet using hand calculations and FEA
- Present completed designs for peer and executive review
- Integrate with existing CFS methodologies and best practices for completion of analysis and documentation material
- CAD and Drafting of components
- Develop test plans and support in test execution
- Support production including time on the production floor
- Design test or tooling hardware (if required) to support the CS Magnet
What we’re looking for:
- Bachelor’s degree in Mechanical Engineering or related field
- Some industry experience (including internship)
- 3+ years experience in aerospace, marine, civil structures, or other heavy engineering field
- Dynamic electromagnetic loading on structures
- Prior work on superconducting magnet design
- Prior work on vacuum vessel design
- Prior work on epoxy resin systems and composite layups
- Analysis of thermal conduction and transients
- Experience supporting a prototype or production environment
- CAD (NX preferred)
- Mechanical FEA (Ansys preferred)
- Mechanical first principles
- Conversational understanding of thermal and electrical resistance networks
- Conversational understanding of fluid dynamics
Bonus points for:
- Familiarity with Maxwell’s equations
- Strong presentation and technical communication skills
- Python and MATLAB familiarity
Must-have Requirements:
- Ability to occasionally lift up to 50 lbs
- Perform activities such as typing, standing or sitting for extended periods of time - Inspection of magnets on the production floor may require leaning, crawling, or other irregular movement patterns. This may be needed infrequently during production support
- Willingness to travel or work required nights/weekends/on-call occasionally
- Work in a facility that contains industrial hazards including heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics
#LI-Onsite
At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.
We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.
This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.
90000 - 145000 USD a year
Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:
• Competitive compensation with equity
• 12.5 Company-wide Holidays
• Flexible vacation days
• 10 sick days
• Generous parental leave policy
• Health, dental, and vision insurance
• 401(k) with employer matching
• Professional growth opportunities
• Team-building activities